feat: add git-spice integration via new Stacks pane

[josephschmitt]

PR Description

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A note on scope

I want to acknowledge upfront that this PR introduces an external integration with https://github.com/abhinav/git-spice, a tool that extends Git with stacked branch workflows. This isn't core Git functionality, and I completely understand if that puts it outside the scope of what lazygit wants to support. If you decide this doesn't belong in this project, I'll be disappointed, but understand completely.

That said, after using git-spice alongside lazygit for the past year, I found myself constantly context-switching between the terminal and lazygit. The experience of managing stacked PRs felt incomplete. I looked for a plugin system to contribute this without touching the main codebase, but couldn't find one: so here I am with a PR instead.

I also want to acknowledge that I've implemented support for git-spice specifically, rather than building a generic "stacked branch tool" abstraction. This was a practical decision: git-spice is the tool I know and use daily, and trying to abstract across multiple stacking tools (graphite, ghstack, etc.) would have significantly increased complexity without even knowing if you'd accept this feature. If maintainers feel a more generic approach would be preferable, I'm open to discussing that.

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What is git-spice?

https://github.com/abhinav/git-spice is a CLI tool that helps manage stacked pull requests, a workflow where you break large changes into a chain of dependent, reviewable PRs:

 main
  └── feat/auth-base (#101)
       └── feat/auth-api (#102)
            └── feat/auth-ui (#103)

Instead of one massive 2000-line PR, you get three focused, reviewable PRs that build on each other. git-spice handles the complexity of:

• Keeping branches rebased on their parents
• Submitting/updating PRs for the entire stack
• Navigating between branches in the stack
• Syncing with remote and cleaning up merged branches

This workflow is increasingly popular (see Graphite, ghstack, Stacked Git) because it leads to faster reviews, cleaner history, and more incremental development.

The irony is not lost on me that I'm claiming to be a proponent of smaller, more focused PR's while myself trying to contribute a massive PR. However I actually built this feature using stacked PR's (see the screenshots), just figured it'd be easier to have this reviewed in one shot vs... 10

What this PR adds

A new Stacks pane (tab alongside Branches, Remotes, Tags) that provides native git-spice integration:

Visual tree display:

         ┌──◯ feat/auth-ui
         │   #103 open
       ┌─┴● feat/auth-api (✓ ↑2)
       │   #102 open ⟳ restack
     ┌─┴◯ feat/auth-base
     │   #101 merged
 main

Full commit operations - squash, fixup, reword, drop, edit, amend, reset (same keybindings as the Commits pane)

Branch operations - checkout, create, delete, move up/down in stack

Stack operations menu (S key):

• Restack branch/all
• Submit branch/all (with options for draft, update-only)
• Sync repo (pull + delete merged branches)

Navigation menu (G key): - Navigate up/down/top/bottom of stack

Two display formats - Short (hierarchy only) or Long (with PR status, sync indicators, individual commits)

Diff integration - Select any branch or commit to see its diff in the main panel

Following lazygit conventions

I've tried hard to make this feel native to lazygit:

• Same keybindings - s for squash, f for fixup, Space for checkout, etc.
• Same patterns - Uses ListControllerTrait, withItem(), require() disabled reasons
• Same menus - Operations menu (S), copy menu (y), reset menu (g)
• Same diff behavior - Selecting items shows diff in main panel
• Same navigation - Enter to drill into commits/files, Escape to go back
• i18n support - All 58 user-facing strings are translatable
• Integration tests - 7 test files covering core functionality

Minimal blast radius

This feature is designed to be completely optional:

1. Disabled by default if gs not installed - The Stacks tab doesn't even appear unless gs is in PATH
2. Config flag to disable - Users can set git.spice.enabled: false
3. No changes to existing behavior - All modifications to existing files are additive

Testing

• Unit tests for tree rendering
• 7 integration tests covering:
  • Basic display
  • Branch checkout/create/delete
  • Log format toggle
  • Navigation menu
  • Stack operations menu

Configuration

 git:
   spice:
     enabled: true      # Enable git-spice integration (default: true)
     logFormat: "short" # Display format: "short" or "long"

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I'm happy to address any feedback, split this into smaller PRs if helpful, or discuss alternative approaches. Thanks for considering this! I really hope I don't have to maintain a fork of this project just to keep this feature 😅.

Please check if the PR fulfills these requirements

• Cheatsheets are up-to-date (run go generate ./...)
• Code has been formatted (see here)
• Tests have been added/updated (see here for the integration test guide)
• Text is internationalised (see here)
• If a new UserConfig entry was added, make sure it can be hot-reloaded (see here)
• Docs have been updated if necessary
• You've read through your own file changes for silly mistakes etc